Wastewater streams often contain appreciable amounts of various salts. Because an increasing number of countries are passing laws to regulate wastewater disposal, it is often difficult or problematic to dispose of contaminated wastewater. Further, mixed salts are often subject to strict regulations on disposal as well. Therefore, to simplify the disposal of wastewater, it is necessary to selectively remove the contaminants in a cost-effective way. Some salts, such as sodium chloride and sodium sulfate, have value if they can be recovered with a relatively high purity and in a cost effective way. But the challenge is meeting both of those requirements.
Therefore, there is a need for an efficient and cost effective process for treating waste streams and brines that contain sulfate and chloride by removing both sulfate and chloride and at the same time producing sodium sulfate and sodium chloride of a relatively high purity that enables them to be sold.